This invention relates to asphalt paving planers wherein a rotatable drum is employed having cutting elements spaced thereabout in a V-spaced pattern in such a manner to cause the cuttings to move from outer portions of the drum toward the center. U.S. Pat. No. 3,606,468 is illustrative of such a drum structure, but a reduction gear of a very elaborate type is necessitated for driving same. Moreover, the device illustrated in this patent has the added disadvantage of a conveyor which delivers the cuttings rearwardly of the planing apparatus necessitating the dump truck or other vehicle receiving the cuttings to be backed up behind the planning apparatus and to be backed up during the entire planing operation of the apparatus. This causes the cuttings to be dropped on the surface which has already been planed requiring a further expensive cleanup operation. Another example of a device employing drum cutters is illustrated in U.S. Pat. No. 3,829,161 which illustrates an apparatus wherein the roller is rotated in a direction opposite to the direction of forward movement of the roller with respect to the road surface.
While prior art machines have generally been able to cut the roadlike surface, the problem of efficiently gathering the cuttings from the cutting drum and loading them into a truck has remained unsolved. The power transmission means from the machine mounted engine to the cylindrical cutting drum has also been a source of many problems on previous machines because the hardness and the variations in hardness of the material being cut, and the variations in the depth of cut tend to create vibrations and shock loads in this power transmission application. The hydraulic transmissions, the gear transmissions and the chain transmissions have all encountered a high incidence of failure due to fatigue and momentary overloads when the cutting drum engaged metal objects such as drainage structures in roadways.
An important object of the invention, therefore, is to provide a machine in which the combination of a vertically slideable scraper blade behind the cylindrical cutter gathers the cut material and cleans the newly cut surface, and an inclined belt conveyor in front of the cutter on which the charging end is close to the cutter and above the material to be cut and on which the discharge end is elevated high enough above the roadlike surface to allow the cut material to be discharged into a truck traveling ahead of and in the same direction as the machine.
The cutter drum which has a large enough diameter and turns at a sufficient speed to eject the cut material onto the charging end of the conveyor is driven through a transmission that can be disengaged by means of a clutch on the engine. The transmission consists of a V-belt drive from the engine-mounted drive shaft to the gear reduction unit mounted in one end of the cylindrical cutter drum. By the use of the V-belt drive, the shock loads encountered by the cutting action of the cylindrical cutting drum are absorbed by the elastic quality of the belts and overload protection is provided in the transmission by the ability of the V-belt drive to slip when an object that cannot be cut is encountered.
Accordingly, it is an important object of this invention to provide for more efficient collection of asphalt cuttings and the like removed by a road planer.
Another important object of this invention is to provide for more efficient removal of cuttings by providing a more efficient drive which is capable of delivering high power from an internal combustion engine operated at high speed, but which will avoid damage thereto as when the cutting drum hits an obstacle as it often does, such as a manhole.
Since the cuttings are more efficiently removed, the reclaimation process is more efficient in that more asphalt is recovered through an efficient, inexpensive device operated with greater efficiency and less downtime.